Pennsylvania MUTCD

Traffic Signals

The current
layout is to have all yellow signals with 12-inch indicators on mast
arms with a black back plate. The turn signal will cycle green
arrow, yellow arrow, then red. During the flash mode, turn signals
will be entirely out as Pennsylvania does not flash arrows. In
cities and boroughs, this convention is not always followed.
Where mast arm installations are not feasible, wire span
installations use the same convention.

Although
not endorsed by PennDOT, sometimes you will come across a signal
installation with turn signals that utilize red arrows. These
are usually ones installed independently by boroughs or cities.
Many installations in Philadelphia
use turn signals with red arrows.

The second largest city, Pittsburgh,
uses signals such as these and has at least one installation with red arrows.

At some
smaller intersections, the "doghouse" signal is utilized,
since it does the job of two signals in the area of one. These
are also used at large intersections where a route will leave one
alignment and turn onto another, to keep the traffic flowing.

Sometimes
this signal is used at intersections instead of the dog house for
turn sequences. A rare sight in most of Pennsylvania, this
signal can be seen extensively in District 6, around the
Philadelphia suburbs. Installations such as PA
611 and Wyandotte Road in Willow Grove or US
40 and Fifth Avenue in Brownsville use these protected/permissive turn signals.

Even more rare than the inline four indicator is the
inline five indicator turn signal which operates on the same
principal as the doghouse above. I've only seen one used on a
state highway and that is PA
271 at Washington Street in Johnstown, but there are two on
the circular route that surrounds Westmoreland Mall in
Greensburg. One at the entrance
ramp from US 30 and the other at the entrance
from old US 30.

At some
intersections you might come across signals with strobe bars in the
red light housing. These are mainly used where there is a high
number of accidents due to "red light running."
These are used at US 30 at Beatty
County Road in Greensburg, US 22 at Resort Plaza Drive in
Blairsville, and Business US 22 at PA 791 in Wilkins Township to
name a few.

Where fire
stations are located along busy highways, signals such as these
may be placed. You aren't seeing things, in standard mode a
yellow indicator flashes in the place of the green indicator.
When an emergency vehicle needs access, the signal goes to yellow
then red and back to flash. I have also seen this type used at
plant and truck
terminal entrances as well as a railroad
crossing.

Although not
extensively used in Pennsylvania, there are two places that use
traffic signals as ramp meters: I-476
in Philadelphia and US 22 in Allentown-Bethlehem. Ramp meters
have been talked about for years for being the solution to traffic
jams in Pittsburgh caused by the Fort Pitt and Squirrel Hill
Tunnels. The signals are coordinated to allow only a certain
number of cars onto the expressway so as to regulate the flow of
traffic and to avoid congestion. Usually when the signal turns
green, only one car may enter the flow of traffic. Other parts
of the country have more extensive systems in operation, and can be
explored on Adam Froehlig's Ramp
Meters page.

The Turnpike
Commission has signals like these at the toll plazas. The signal
on the left is used on the main Turnpike in all lanes.
Ticket customers will just see the green and red cycles, but E-ZPass
users can get all three: green for payment, yellow if the
account balance is low, and red if there is an error. The
signal on the right is for the extensions. If you fail to pay,
the rotating light on top lights and a siren will sound.

With the
introduction of E-ZPass on the mainline Turnpike, these
installations have been installed over the respective lanes.
The signals sequence from flashing yellow (E-ZPass Only), green
(E-ZPass and tickets), or red (closed).

At the
entrances to the Fort Pitt and Squirrel Hill Tunnels in Pittsburgh,
you'll see these signals. They will turn on if an overheight
truck is heading to the portal or if there is congestion (which is
every rush hour) before the tunnel to alert drivers to be prepared
to stop.

Pennsylvania complies with the Federal Highway
Administration's guidelines for signaling of highways. Below are some
exceptions that are not covered in the United States Manual of Uniform Traffic
Control Devices.

Early layouts had all
the signals on wires. The turn signal would cycle green arrow
and red light (this was a protected turn), then yellow arrow, then
red. These are still in existence today, but are being
replaced slowly.

Some of the
early turn signals would use a circular yellow indicator instead of
an arrow. There was an example of this in use at the
intersection of Industrial
Boulevard and PA
982 in Derry.

Older
signals around the City of McKeesport area in Allegheny County have
an unusual sequence. They still maintain green-yellow-red
progress, but add a small delay in between each indication.
Coming up to one that just changed yellow, one might think that the
signal is in flash mode. The signal at West
Fifth Avenue and Romine Avenue still uses these old timers.

Older
Pittsburgh signals used to use a weird sequence. The signals
would go green-green/yellow-yellow-red. The odd green/yellow
phase was meant as a pedestrian phase to alert them that the signal
would be changing to red and not to cross. However, motorists
detested the sequence and felt it was too confusing, so it was axed
in the mid-1980s. Current Pittsburgh signals, and hold-overs
from that era use the green-yellow-red sequence.